In the past decade, an increasing body of evidence has indicated that sleep disturbances and disorders are intricately connected to adolescent physical and mental health. However, there is a paucity of research that has investigated sleep as a modifiable mechanism that may improve medical rehabilitation and mental health treatments and inform health policies in vulnerable populations of adolescents with chronic physical disabilities. In particular, adolescents with spina bifida (SB) are at-risk for a range of emotional and cognitive difficulties, including depression and attention deficits, as well as significant functional impairment. Sleep- wake disturbances, such as difficulty falling asleep, frequent nighttime awakenings, and excessive daytime fatigue, are especially prevalent in youth with chronic illnesses and neurological disorders. However, few studies have considered the deleterious impact of disturbed sleep on physical and psychological health in adolescents with SB. Thus, the aims of this project are to 1) comprehensively examine sleep-wake patterns in adolescents with SB using subjective and objective measures of sleep, 2) identify the relationship between sleep-wake disturbances and physical and psychological functioning in adolescents with SB, and 3) identify daily temporal associations between sleep and mood in adolescents with SB. This study will examine sleep- wake patterns in adolescents ages 12 to 17 with SB (N = 40) compared to a matched comparison group of typically developing peers (N = 40). A subjective and objective sleep assessment will be conducted; ambulatory actigraphic recordings will be completed over 10 days, and adolescents will complete several sleep questionnaires (e.g., sleep quality, pre-sleep arousal) and a daily sleep diary. In addition, adolescents and parents will undergo a semi-structured diagnostic interview and complete symptom questionnaires to assess depression and attention deficits, and health-related quality of life. Knowledge gained from this study will be the first step in elucidating modifiable secondary conditions to improve physical and mental health outcomes in chronically physically disabled adolescents with SB, and provide the applicant with research training to develop an independent research program in this area